Means for protecting ships against underwater explosion



Sept. 25, 1945- v. s. MAKAROFF ETAL 2,335,417

MEANS FOR PROTECTING SHIPS AGAINST UNDERWATER EXPLOSION Filed Dec. 9,1942 Fl G.i F I (2.2

INVENTORS luv ATTORNEY 1 00v! (SiM/(AFOFF Y MCHOLAS aARTSAY PatentedSept. 25, 1945 MEANS FOR PROTECTING SHIPS AGAINST UNDERWATER EXPLOSIONVadim S. Makaroif and Nicholas C. Artsay,

New York, N. Y.

Application December 9, 1942, Serial No. 468,436

2 Claims.

This invention relates to means and method for protecting ships againstunderwater explosions and has particular reference to means and methodsfor building or reinforcing ships in such manner that the effect ofexplosions as-caused by torpedoes or mines is greatly reduced or" evenentirely suppressed.

This invention has for its object to provide a ship with protectinglayers on the underwater portions of its hull, the layers being soconstructed as to absorb the energy of an underwater explosion. i

The protective layer for the hull, according to our invention, consistsof a combination of at least two materials, each of which, if usedalone, would not afford sufiicient protection. The two materials can becombined in a single unit but they must retain their individualproperties, however thoroughly they may be mixed. One example of suchmaterial is wet wood which comprises fibrous particles, destructibleunder action of explosive forces, and water or moisture which acts as aconductant of detonation. Another example is a special form of concreteor similar mouldable composition in which particles of light,destructible material are mixed with cement.

A homogeneous material, if used alone, would not afford the desiredprotection, even when used in relatively large quantities.

Our invention is more fully explained by way of examples in theaccompanying specification and drawing, in which: v

Fig. 1 is a fractional sectional view of the hull of a ship in which wetwood is employed as protective material;

Fig. 2 is a similar view of a modified construction also using wet wood;Y

.Fig. 3 is a detail sectional view taken on the line 3-3 of Fig. 1;

Fig. 4 is a fractional sectional view of the hull of a ship in which aspecial cement or concrete composition is used; and

Fig. 5 is a similar view of struction.

In one form of my invention the protective layer for a ship I consistsof a plurality of superimposed timbers attached to the hull 2 of theship.

To obtain the best results, the timbers are preferably arrangeddiiferently on dillerent portions of the hull. At the middle shorttimbers 3 are placed vertically, being held at the ends betweenlongitudinally extending I-beams or T- bars 4. Below these verticaltimbers there are a modified ship concurved vertically extending T-bars5, holding the ends of horizontally extending timbers 6. These timbersform the first layer, to which additional layers of vertical timbers, l,8, 9; etc. are attached by screws I d. The screws are relatively shortjoining not more than two timbers so that in the event of an explosionwhen the outer layers are destroyed; the screws would not pierce thehull plates.

The'upper ends of the timbers rest against a horizontal plate ll,supported by brackets I2, and reinforced by channels l5. The lowermostcurved portion of the protective covering is built up of filling piecesl3, arranged in convenient lengths. The timbers are enclosed in a, thinsheet iron covering [4. A similar covering or sheathing is provided forupper timbers l6, tapering upward toward the hull from the plate I I.

According to our investigations, the wet wood represents a verysatisfactory material for .protecting the hull against underwaterexplosions, because such wood actually consists of two materials orsubstances; the fibrous body, which can be readily crushed and evencomminuted by the force of explosion, thereby reducing the pressure andtemperature of the gases of explosion, and water or moisture, forming awinding path for the rapid spread of detonation to adjacent portions ofwood, thereby greatly increasing the volume of destruction andcorrespondingly reducing the force, acting on the plates of the hull.With a reasonable thickness of our protective layer-it is possible so toreduce the effect of the forcev of explosion of a one thousand poundcharge, for instance, that only a relatively harmless puncture willresult in the hull plates, without any harmful effect on other parts ofthe ship.

The wood must be wet, however,- in order to provide the maximum ofprotection. For this purpose the timbers must not'be joined together tootightly, and it is even desirable to leave large wedge-shaped clearancesI'l between the timbers as shown in Fig. 3, leaving also a few holes inthe sheathing H! for admitting sea water between the timbers.

The foregoing construction is especially suitablefor reinforcing orprotecting old or already built ships. For new ships l8 it is preferredto use a simplified constructionshown in Fig. 2, the timbers 1, 8, 9,etc. being placed on the recessed hull plates 20, so that the ships hullcan have a single curvature thereby facilitating arrangement of woodprotection and of its upper framing. The lower ends of the timbers aretrimmed to suit the hulls other curvature. An outer thin iron sheathingI9 is provided over the timbers to receive paint and to protect the woodagainst marine borers and barnacles. It need not be water tight.

Good results can be also obtained by using a mouldable material 28 asshown in Fig. 4, by pouring the material into a space between thetemporary outer form 2!, and the hull proper 22, upper plate 23, and alower retaining or bilge keel frame 24. Supplementary chambers areformed under the frame 24 in front of a keelson 25, also filled with thesame mouldable material 28 for transmitting the compression forces totwin bottom framing and plating.

Any suitable composition can be used for filling the chambers at thesides of the hull, provided the composition consists of at least twodistinctly different substances, having the required properties asexplained above. We prefer to use for this purpose, however, a specialconcrete mixture, in which sand and gravel are replaced by a light,destructible material such as kieselguhr, pumice stone, properly sizedcoke, crushable stone, etc., cement which is used as a binder, servingalso as a conductor of the detonation waves. Such a reinforcement iswell suited for warships, Fig. 4, representing a diagrammatic section ofa battleship 29. Metal reinforcements may be used for imparting greaterstrength to the moulded material, the reinforcements being in the formof hooked rods 26, locked to the T-bars 4, also interlocked hooked rods21 extending partly transversely and partly longitudinally.

A satisfactory protection can be also obtained by using a fluid orsemi-fluid composition, such as a mixture of heavy tar and coke or heavytar and small blocks of wood, filling the compartments or chambersbetween the inner strong wall 22 of the hull and a very light outer hullor blisters 2|. In this case the heavy tar will serve as detonation waveconductant.

Our invention is not restricted to the protection of the sides of theship but can be used for protecting the bottoms as well.

A relative degree of protection can be also obtained by adding crushablematerial such as pumice stone in adequate quantity to the water or fueloil in existing tanks in the ship, in Wing compartments or in a doublebottom.

The protection as described is readily adaptable also for ships oftensubject to explosions at some distance from their hulls, for instancesubmarine boats when attacked with depth charges, also ships subject toaerial bombardment, when many near misses may'disable the ships withoutdirect In this case the blast (sound wave) due to xpansion of gas bubbledoes most of the damage and the interposition of a relatively thin layerof crushable material will absorb the energy of the wave and protect theship plates behind. The

ends of the timbers,

use for this purpose of wood sheathing is preferred.

The protective material may be placed in compartments 30, 3|, and underthe bottom 32 of the ship 33, as shown in Fig. 5, behind ordinary emptyblisters 34.

The painted sheet iron covering or sheathing for wood or otherprotective material is intended as a defense against borers andbarnacles and can be increased in thickness if saving in weight is notof any great importance. The purpose of such a covering is to preventthe gas at high pressure during the beginning of the second phase frompenetrating the wood or other protection laterally thereby subsequentlyweakening the whole protective structure and its bond with the hull. Ascertain experiments have indicated, a thin steel plating laid over anelastic or yielding material is not destroyed by the force of explosionsbecause, due to its thinness and flexibility, the plating readilyaccelerates and transmits detonation waves and gas pressure to thematerial behind. Thus it is possible to facilitate the lateral expansionof explosion gas from the initial depression in the'protective layer,directing it outward by the relatively smooth steel surface instead ofjagged perifery of the remaining protective material. It appears as ifthe additional thickness of steel plating over Woodor other protectivematerial causes glancing of the expanding gas over the perifery ofresidual protective material with a consequent reduction of damage tothe protective structure and to its backing; small holes can be providedin the plating for allowing access of water to the wood.

It is understood that our means and method for protecting ships againstunderwater explosions may be further modified Without departing from thespirit of the invention as set forth in the appended claims.

We claim as our invention:

1. Means to protecta ship against an underwater explosion comprising aplurality of superimposed layers of timbers at the side of the hull ofthe ship; means to fasten each succeeding layer to the preceding layer;and means to support the the timbers being disposed with clearancestherebetween for admitting water from the outside of the hull. I I

2. Means to protect a ship against an underwater explosion comprising aplurality ofsuperimposed layers of timbers at the side of the hull ofthe ship, said timbers extending in a substantially vertical direction;means to fasten the timbers to the hull, the timbers being provided withclearances therebetween for admitting water thereby maintaining thetimbers in a wet state.

VADIM s. MAKA OFF. NICHOLAS c. ARTSAY.

